Allah sends His Salat (Graces, Honours, Blessings, Mercy, etc.) on the Prophet (Muhammad SAW) and also His angels too (ask Allah to bless and forgive him). O you who believe! Send your Salat on (ask Allah to bless) him (Muhammad SAW), and (you should) greet (salute) him with the Islamic way of greeting (salutation i.e. AsSalamu 'Alaikum).
निस्संदेह अल्लाह और उसके फ़रिश्ते नबी पर रहमत भेजते है। ऐ ईमान लानेवालो, तुम भी उसपर रहमत भेजो और ख़ूब सलाम भेजो